// ECMAScript 2016

// Array.prototype.includes -------------
const arr = ['foo', 1, NaN, undefined, null, false]

console.log(arr.indexOf('foo'))
console.log(arr.indexOf('bar'))
console.log(arr.indexOf(null))
console.log(arr.indexOf(undefined))
console.log(arr.indexOf(false))
console.log(arr.indexOf(NaN))
console.log(arr.includes('foo'))
console.log(arr.includes(undefined))
console.log(arr.includes(NaN))

// 指数运算符

// console.log(Math.pow(2, 10))
console.log(2 ** 10)